Which of these equations correctly expresses the self-ionization of water?
Upper H subscript 2 upper O superscript plus upper H subscript 3 upper O superscript plus double-headed arrow upper H subscript 2 upper O plus upper O upper H superscript minus.
Upper H subscript 2 upper O plus upper H subscript 2 upper O double-headed arrow 2 upper O upper H superscript minus.
Upper H subscript 2 upper o plus upper H subscript 2 upper O double headed arrow 2 upper H subscript 3 upper O superscript plus.
Upper H subscript 2 upper O plus upper H subscript 2 upper O double-headed arrow upper H subscript 3 upper O superscript plus, plus upper O upper H superscript minus.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.